Short TCF sequences in the bleaching of Eucalyptus camaldulensis pulp. A comparative study

Abstract

This research was undertaken to evaluate the bleaching response of Eucalyptus camaldulensis in different Totally Chlorine Free (TCF) bleaching sequences. The goal was to compare bleaching sequences, which include a peroxy acid stage - either peracetic acid (Paa) or Caro's acid (Caa)-, to simple hydrogen peroxide bleaching. The E. camaldulensis kraft pulp sample was obtained from a South Asian pulp mill. Its kappa number was 11 and viscosity 1020 mL/g, respectively. According to the results, peracetic acid and Caro's acid proved to be potential additional alternatives for hydrogen peroxide alone. Both of these bleaching agents can be used between oxygen delignification and the final hydrogen peroxide stage for improved brightness stability, as well as reduced hydrogen peroxide consumption. Moreover, they can be used in a bleaching sequence without any major capital investment.